This invention relates to oil and gas drilling, and more particularly to an apparatus for reliably transmitting information through harsh downhole environments. The present invention relates to the field of data transmission systems through downhole components. In the past several decades engineers have been attempting to develop apparatuses to transmit data from a downhole tool string to the surface. Oil companies may use these downhole measurements to make decisions during the drilling process by using sophisticated techniques for systems such as Measurement While Drilling (MWD) and Logging While Drilling (LWD). These techniques typically rely on instantaneous knowledge about the geologic and other formations that are being drilled in order for the dill rig operators to best determine the depth, azimuth, drill speed, weight on bit, and other characteristics desired to complete the borehole formation.
U.S. Pat. No. 6,670,880 to Hall et, al. which is incorporated herein by reference for all that it teaches, discloses a system for transmitting data through a string of downhole components. In one aspect, the system includes first and second magnetically conductive, electrically insulating elements at both ends of the component. Each element includes a first U-shaped trough with a bottom, first and second sides and an opening between the two sides. Electrically conducting coils are located in each trough. An electrical conductor connects the coils in each component. In operation, a varying current applied to a first coil in one component generates a varying magnetic field in the first magnetically conductive, electrically insulating element, which varying magnetic field is conducted to and thereby produces a varying magnetic field in the second magnetically conductive, electrically insulating element of a connected component The magnetic field thereby generates a varying electrical current in the second coil in the connected component.
Downhole information may help a drilling crew to make decisions in real time. This may save the crew time and money. In inductive transmission systems, magnetically conductive materials are affected by varying temperatures in downhole environments. When a magnetically conductive material reaches its curie temperature it looses its magnetic properties.
U.S. Patent application 20040144541 to Picha, which is incorporated herein by reference for all that it teaches, discloses an embodiment of a system configured to heat at least a part of a subsurface formation. The system comprising: an AC power supply; one or more electrical conductors configured to be electrically coupled to the AC power supply and placed in an opening in the formation At least one of the electrical conductors comprises a heater section. The heater section comprising an electrically resistive ferromagnetic material configured to provide an electrically resistive heat output when AC is applied to the ferromagnetic material. The heater section is then configured to provide a reduced amount of heat near or above a selected temperature during use due to the decreasing AC resistance of the heater section when the temperature of the ferromagnetic material is near or above the selected temperature; and wherein the system is configured to allow heat to transfer from the heater section to a part of the formation. The ferromagnetic material may comprise two or more ferromagnetic materials with different Curie temperatures.